X Version 11 (1 September 1988) XGrabKey(XS)
NAME
XGrabKey, XUngrabKey - grab keyboard keys
SYNTAX
XGrabKey(display, keycode, modifiers, grab_window,
owner_events, pointer_mode,
keyboard_mode)
Display *display;
int keycode;
unsigned int modifiers;
Window grab_window;
Bool owner_events;
int pointer_mode, keyboard_mode;
XUngrabKey(display, keycode, modifiers, grab_window)
Display *display;
int keycode;
unsigned int modifiers;
Window grab_window;
ARGUMENTS
display Specifies the connection to the X server.
grab_window
Specifies the grab window.
keyboard_mode
Specifies further processing of keyboard events.
You can pass GrabModeSync or GrabModeAsync.
keycode Specifies the KeyCode or AnyKey.
modifiers Specifies the set of keymasks or AnyModifier. The
mask is the bitwise inclusive OR of the valid
keymask bits.
owner_events
Specifies a Boolean value that indicates whether
the pointer events are to be reported as usual or
reported with respect to the grab window if
selected by the event mask.
pointer_mode
Specifies further processing of pointer events.
You can pass GrabModeSync or GrabModeAsync.
DESCRIPTION
The XGrabKey function establishes a passive grab on the
keyboard. In the future, the keyboard is actively grabbed
(as for XGrabKeyboard), the last-keyboard-grab time is set
to the time at which the key was pressed (as transmitted in
the KeyPress event), and the KeyPress event is reported if
all of the following conditions are true:
⊕ The keyboard is not grabbed and the specified key
(which can itself be a modifier key) is logically
pressed when the specified modifier keys are logically
down, and no other modifier keys are logically down.
⊕ Either the grab_window is an ancestor of (or is) the
focus window, or the grab_window is a descendant of the
focus window and contains the pointer.
⊕ A passive grab on the same key combination does not
exist on any ancestor of grab_window.
The interpretation of the remaining arguments is as for
XGrabKeyboard. The active grab is terminated automatically
when the logical state of the keyboard has the specified key
released (independent of the logical state of the modifier
keys).
Note that the logical state of a device (as seen by client
applications) may lag the physical state if device event
processing is frozen.
A modifiers argument of AnyModifier is equivalent to issuing
the request for all possible modifier combinations
(including the combination of no modifiers). It is not
required that all modifiers specified have currently
assigned KeyCodes. A keycode argument of AnyKey is
equivalent to issuing the request for all possible KeyCodes.
Otherwise, the specified keycode must be in the range
specified by min_keycode and max_keycode in the connection
setup, or a BadValue error results.
If some other client has issued a XGrabKey with the same key
combination on the same window, a BadAccess error results.
When using AnyModifier or AnyKey, the request fails
completely, and a BadAccess error results (no grabs are
established) if there is a conflicting grab for any
combination.
XGrabKey can generate BadAccess, BadValue, and BadWindow
errors.
The XUngrabKey function releases the key combination on the
specified window if it was grabbed by this client. It has
no effect on an active grab. A modifiers of AnyModifier is
equivalent to issuing the request for all possible modifier
combinations (including the combination of no modifiers). A
keycode argument of AnyKey is equivalent to issuing the
request for all possible key codes.
XUngrabKey can generate BadValue and BadWindow error.
DIAGNOSTICS
BadAccess A client attempted to grab a key/button
combination already grabbed by another client.
BadValue Some numeric value falls outside the range of
values accepted by the request. Unless a specific
range is specified for an argument, the full range
defined by the argument's type is accepted. Any
argument defined as a set of alternatives can
generate this error.
BadWindow A value for a Window argument does not name a
defined Window.
SEE ALSO
XAllowAccess(XS), XGrabButton(XS), XGrabKeyboard(XS),
XGrabPointer(XS)
Xlib - C Language X Interface
(printed 2/12/90) (1 September 1988) XGrabKey(XS)